Items tagged “normal variant”

116 results found
Article

Aberrant right subclavian artery

Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are among the commonest aortic arch anomalies.  Epidemiology The estimated incidence is 0.5-2% 1. Associations as can be expected from the embryological development of the artery, the right recurrent laryngeal nerve...
Article

Variant anatomy of the aortic arch

Variant anatomy of the aortic arch occurs when there is failure of normal aortic development. It results in a number of heterogenous anomalies of the aorta and its branch vessels. Gross anatomy Normally, the aorta ascends in the superior mediastinum to the level of the sternal notch before arc...
Article

Os acromiale

Os acromiale is an anatomical variant and represents an unfused accessory center of ossification of the acromion of the scapula. Epidemiology Os acromiale is relatively common, seen in ~8% (range 1-15%) of the population 1,2 and can be bilateral in 60% of individuals 5. Clinical presentation ...
Article

Os odontoideum

Os odontoideum (plural: ossa odontoidea) is an anatomic variant of the odontoid process of C2 and needs to be differentiated from persistent ossiculum terminale and from a type 2 odontoid fracture. It can be associated with atlantoaxial instability.  Although it was originally thought to be a c...
Article

Persistent carotid-vertebrobasilar anastomoses

The persistent carotid-vertebrobasilar anastomoses are variant anatomical arterial communications between the anterior and posterior circulations due to abnormal embryological development of the vertebrobasilar system. They are named, with the exception of the proatlantal artery, using the crani...
Article

Persistent otic artery

The persistent otic artery is one of the persistent carotid-vertebrobasilar anastomoses, although there is considerable controversy in regards to its existence. It is said to arise from the C2 (petrous) segment of the internal carotid artery within the carotid canal. This artery emerges from the...
Article

Persistent hypoglossal artery

A persistent hypoglossal artery is one of the persistent carotid-vertebrobasilar anastomoses. It is second in frequency to the trigeminal artery which is present approximately six times as often.  It arises from the distal cervical ICA segment, usually between the C1 and C3 vertebral level. Aft...
Article

Basilar artery fenestration

Basilar artery fenestration (or more simply, basilar fenestration) is the most common intracranial arterial fenestration and most common congenital anomaly of the basilar artery. This anatomic variant is characterized by duplication of a portion of the artery that are connected proximally and di...
Article

Os peroneum

An os peroneum is a small accessory bone of the foot located at the lateral aspect of the cuboid within the substance of the fibularis longus tendon as it arches around the cuboid. Epidemiology It is a very common anatomical variant, seen in up to 26% of feet 1. Differential diagnosis It sho...
Case

Supracondylar process of humerus

  Diagnosis certain
Maulik S Patel
Published 18 Mar 2010
79% complete
X-ray
Article

Developmental anomalies of the kidney and ureter

Developmental anomalies of the kidneys and ureters are numerous and not only potentially render image interpretation confusing but also, in many instances, make the kidneys more prone to pathology: number renal agenesis supernumerary kidney fusion horseshoe kidney: most common cross fused ...
Case

Replaced left and right hepatic arteries

  Diagnosis certain
Hani Makky Al Salam
Published 15 Jun 2010
62% complete
CT
Article

Os trigonum

The os trigonum (plural: ossa trigona) is one of the ossicles of the foot and can be mistaken for a fracture.  It sits posterior to the talus on the lateral foot radiograph and represents a failure of fusion of the lateral tubercle of the posterior process. It is estimated to be present in ~7% ...
Case

Azygos fissure

  Diagnosis not applicable
Hani Makky Al Salam
Published 02 Aug 2010
44% complete
X-ray
Case

Azygos fissure

  Diagnosis not applicable
Hani Makky Al Salam
Published 15 Aug 2010
32% complete
X-ray
Article

Os calcaneus secundarius

An os calcaneus secundarius is an accessory ossicle of the anterior calcaneal process present in up to 5% of the population at cadaveric examination. The ossicle can be a cause of ankle pain and may mimic bifurcate ligament avulsion fracture of the anterior calcaneal process. Differential diagn...
Article

Patent urachus

A patent urachus is one of the spectrum of congenital urachal anomalies. It has occasionally been termed "urachal fistula". Clinical presentation A patent urachus is often diagnosed in neonates when urine is noted leaking from the umbilicus. The umbilicus may also have an abnormal appearance o...
Article

Bipartite patella

A bipartite patella (two-part patella) is a patella with an unfused accessory ossification center, typically at the superolateral aspect. Epidemiology The superolateral accessory ossification center of the patella is usually present by 12 years of age and may persist into adult life. Bipartite...
Case

Cervical rib

  Diagnosis certain
Hani Makky Al Salam
Published 02 Nov 2010
69% complete
X-ray
Case

Biliary tree anatomical variant - biliary trifurcation

  Diagnosis not applicable
Hani Makky Al Salam
Published 12 Dec 2010
50% complete
MRI

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